Werkwinkel 12(1), 2017, pp. 7-17 © Department of Dutch and South African Studies Faculty of English, Adam Mickiewicz University, Poznań, Poland DOI: 10.1515/werk-2017-0001 The Australopithecines – An Extinct Group of Human Ancestors: My Scientifi c Interest in South Africa KATARZYNA A. KASZYCKA Adam Mickiewicz University Zakład Ekologii Ewolucyjnej Człowieka Instytut Antropologii Uniwersytet im. Adama Mickiewicza ul. Umultowska 89 61-614 Poznań, Poland [email protected] Abstract: I introduce the subject of my research interest in South Africa – the australo- pithecines – a group of bipedal, small-brained and large-toothed creatures from the Plio- -Pleistocene, from which the human genus arose. I then briefl y discuss various topics of my research, concerning: (1) Taxonomic status and morphological description of the ex- tinct human relative from the Kromdraai site (Australopithecus robustus); (2) Graphic recon- struction of the partial skull from Kromdraai – specimen numbered TM 1517; (3) Assess- ment of size sexual dimorphism of the South African australopithecines (Australopithecus robustus and Australopithecus africanus), which, in terms of facial features, was pronounced – being almost gorilla-sized; (4) Social behavior of a fossil hominid species from around 2 million years ago, which, in terms of the social structure, was most likely a multimale- -multifemale one; and (5) An event from the history of paleoanthropology, concerning the content of the 1924/25 photographs of the Taung Child (Australopithecus africanus) – the fi rst australopithecine skull discovered. Keywords: paleoanthropology; South Africa; australopiths; human evolution werkwinkel 12(1) 2017 8 Katarzyna A. Kaszycka My scientifi c interests have for many years been focused on paleoanthropol- ogy 1 and, in particular, the early African human ancestors. This interest was already begun by the eighth grade of elementary school when the Po- lish translation of the book Man, Time, and Fossils by Ruth Moore fell into my hands. After spending a few years studying biology at the Faculty of Biol- ogy, University of Warsaw, I transferred to Adam Mickiewicz University in Poznań to study biological anthropology. There, I completed my MSc degree writing the thesis entitled “Diversity of the Australopithecines – Taxonomic and Anthropogenetic Consequences” under the supervision of Professor Jan Strzałko. My interests in South Africa arose from a combination of circumstances. In 1990 I enrolled as a graduate student of reputed paleoanthropologist – Profes- sor Milford H. Wolpoff at the University of Michigan, Ann Arbor, Michigan. After spending over three years furthering my studies there, the opportunity arose to travel to South Africa – the place of the fi rst discovery and a repository of the australopithecine fossils – to study the original collections and to make aus- tralopiths the subject of my doctoral thesis. I undertook my fi rst journey there in 1994 – the same momentous year of the fi rst democratic general election and the election of Nelson Mandela as President – and so began my ‘adventure’ with South Africa. 1. The australopiths – the subject of my interest The fossil and genetic evidence show that the history of bipedal primates (hominids) goes back about 6-7 million years. At that time in Africa there lived a common ancestor, from which two evolutionary lineages arose – one that led to us – humans (via the now extinct australopithecines), and the other – to our closest living relatives – the chimpanzees. It is among the australopithecines that the direct ancestors of the human genus should be sought. The term ‘australopithecines’ refers to a group of the Plio-Pleistocene species (dated from 4.0 to 1.2 million years ago) including the extinct ancestors and rela- tives of humans, who lived in broad areas of Africa – from Ethiopia (in the East) to the Republic of South Africa (in the South). While the australopithecines were already bipedal, their brains remained small (approximately 500 cc in volume, compared to an average of about 1,350 cc for modern humans). They had pow- erful jaws and large back teeth adapted for grinding and chewing hard, tough 1 Paleoanthropology – the study of human ancestors from fossils (fossils are the preserved remains of organisms from the distant past). 12(1) 2017 werkwinkel The Australopithecines – An Extinct Group of Human Ancestors... 9 Figure 1. Two australopithecine skulls from South Africa: (left) Australopithecus africanus from Sterkfontein (gracile form) vs. (right) Australopithecus robustus from Swartkrans (robust form) (photos by K.A. Kaszycka) foods. In relation to the australopithecines two descriptive terms are commonly used – the so-called “gracile” and “robust” forms 2 (see Fig. 1). 2. Historic background The history of the South African discoveries of early hominids dates to 1924 when Australian-born anatomist – Professor Raymond Dart from WITS Univer- sity in Johannesburg, obtained the fi rst fossil remains from the Taung site. Dart (1925) named the new species Australopithecus africanus – the “man-ape of South Africa.” We now know of a fair number of fossil-bearing sites across the country. The discovered remains are dated at around 3.0-1.5 million years old, and came mainly from the dolomite caves near Johannesburg (see Fig. 2), located in the Cradle of Humankind – a South African National Heritage site. Aside from Taung, South African australopithecines were also recovered (during the period of Broom’s and Dart’s excavations) from: Sterkfontein (Broom 1936), Kromdraai (Broom 1938), Makapansgat (Dart 1948) and Swartkrans (Broom 1949). In more recent times, several important discoveries were made at Gladysvale (Berger 1992), Gondolin (Menter et al. 1999), Drimolen (Keyser 2000), Cooper’s (Steinin- ger et al. 2008), and Malapa (Berger et al. 2010). 2 Traditionally the “gracile” (lightly built) and “robust” forms of the australopithecines (australo- piths) refer to differences in shape of the skull, size of face, jaws and teeth, as well as diet. werkwinkel 12(1) 2017 10 Katarzyna A. Kaszycka Figure 2. Sterkfontein cave site – place of discovery of Australopithecus africanus (photo by K.A. Kaszycka) Apart from the “Taung Child” (a partial skull together with a natural en- docast 3 of the brain), other best known australopith individuals, who received nicknames, are: “Mrs. Ples” (complete cranium), found by Robert Broom (1947) at Sterkfontein, and “Little Foot” (a spectacular near-complete skeleton), whose bones were fi rst found in 1994 in a box, and subsequently in-situ between 1997-99 by Ron Clarke (1998), also within the Sterkfontein cave system. The most recent discovery included the remains of two individuals (which were given a new spe- cies name – Australopithecus sediba), found at Malapa by Lee Berger in 2008. 3. Status of the Kromdraai hominids My doctoral thesis (completed at the University of the Witwatersrand, Johan- nesburg, under the supervision of Professors Milford Wolpoff and Maciej Hen- neberg) was entitled “Status of Kromdraai: Cranial, Mandibular and Dental Morphology, Systematic Relationships, and Signifi cance of the Kromdraai Hom- inids.” The chosen subject concerned the taxonomic status of a group of robust australopithecines from the Kromdraai site (from which the type specimen 4 of Australopithecus robustus derives), as well their place in human phylogeny. In the paleoanthropological literature there was no then consensus regarding the 3 Endocast – the internal cast of a braincase. 4 Type specimen – the original specimen from which a description of a new species is given. 12(1) 2017 werkwinkel The Australopithecines – An Extinct Group of Human Ancestors... 11 taxonomic status of the robust australopithecines from Kromdraai as they were considered: the same, or a different species than other robust australopiths from the nearby Swartkrans site; a unique ancestor of hominids from Swartkrans; the possible ancestor of Swartkrans hominids and East African Australopithecus boi- sei clade 5; or even a link with the earliest Homo. Focusing on variation, I tested two null hypotheses, attempting to fi nd an- swers to some fundamental questions: What is the specifi c relationship of the hominids from Kromdraai to similar remains from Swartkrans (a single or two species?), and how the Kromdraai australopithecines relate to the origin of the other robust australopiths (including Australopithecus boisei) and the earliest Homo. The answer to the fi rst question was obtained from analysis of the rel- evant morphology and adopting the Evolutionary Species Concept: “A species is a single lineage of ancestral descendant populations of organisms which main- tains its identity from other such lineages and which has its own evolutionary tendencies and historical fate” (Wiley 1978: 18). The answer to the question re- garding the phylogenetic relationships between the taxa 6 studied was revealed through cladistic 7 analysis using the PAUP (Phylogenetic Analysis Using Parsi- mony) computational program in attempting to develop hypotheses of ancestor- -descendant relationships. On the basis of the then available evidence, I concluded that Kromdraai is the most closely related sample to Swartkrans, being most likely an earlier, ancestral representative of the same species – Australopithecus robustus. At the same time, Kromdraai, being more plesiomorphic 8 (Australopithecus africanus-like) than the other robust australopiths (i.e., the Swartkrans sample and Australopithecus boisei), fi ts morphologically as an ancestor